While I have been busy with work, I also had to wait for the black screws I ordered for the case to arrive. MM only included a bunch of (still inadequate) black thumbscrews. The rest of the included screws were silver not quite fitting the case black color. I decided I wanted to use all black screws, possibly the most unnoticeable ones; hence I ordered 6-32 screws 6mm and 9mm lengths with hex button heads. I also ordered black nuts to use with them whenever necessary. Therefore for all visible holes, I will be using these screws, which means even for fans mounts. I did do not want to use the thumbscrews even though they are more convenient since they are too big.
I received the screws today and I am putting the system together. I learned working in the lower level in a horizontal configuration is quite inconvenient. I am sure two level vertical configuration is more convenient. Nevertheless, I do not complain and I still like my choice.
Meanwhile, I have been trying to decide which hard drive to use for data storage. Remember, I mentioned acquiring an IBM M5015 raid controller (same as the LSI 9260-8i) and I planned to set up a raid 5 array for data storage. I almost made my mind to use 2.5” drives. This is because I have realized while the case has enough space to accommodate 3.5" drives (I need 8 units), when I will switch to water-cooling, this can become a problem. With 2.5" drives, there shouldn’t be a problem.
However, it turns out the choice of hard drive is not as smooth and obvious as I thought. There are three possiblities:
i) Using fast SSD drives in a raid 5 (or raid 0) configuration results in an incredibly fast I/O throughput.
Major con: SSD drives with large capacity are extremely expensive.
ii) Using consumer grade hard disk drives: this is pleasantly an inexpensive option which still can yield very good I/O throughput. Nevertheless, after doing extensive research I have learned about a serious burden:
A feature called TLER (Time-Limited Error Recovery) is crucial to lessen the likelihood of the failure of the raid array. It seems the two major hdd manufacturers have decided to exclude this feature from consumer grade hdd’s. Only enterprise level hdd’s feature the function. It may also be called CCTL (Command Completion Time Limit) or, ERC (Error Recovery Control).
An alternative solution would be having a raid card which allows to change the timeout value (the time the raid controller allocates to a given hard drive to do it standard recovery procedure in order to handle an occurring bad sector. At this point, I do not still know if M5015 raid controller would allow this. I will need to check it out.
Another problem: some users have reported poor I/O performance when using consumer grade hdd’s on a raid controller such as LSI 9260. In these situations, manufactures normally respond by saying they do not support the use such hard drives with thier controllers.
WD used to have a utility program which could be used to enable TLER on this class of hard drives. Apparently, in 2009 they decided to ship drives that could not make use of the utility, most likely for marketing reasons: an attempt to force consumers to buy their more expensive enterprise class drives if they wanted to have a raid array. Hence it became impossible to enable TLER.
iii) Using enterprise grade hard disk drives specially made for raid set ups.
Major con: The 2.5" drives are about 4 times more expensive than their consumer grade alternatives while the main useful difference is merely having TLER enabled by default. The 3.5" ones are still reasonably priced.
Your inputs are appreciated if you know a good solution to the dilemma.
Edited by raminux - 6/19/12 at 11:31pm